“Dr. Dykstra has been elaborating it, and data so far have confirmed his beliefs. Today we brought in what may be the crucial measurements—chiefly seismic echoes from depth bombs exploded in undersea wells.”

  “M-m-m, yeah, I do know something about it.” Hawthorne stared across the ocean. No cetoids were in sight. Had they gone down to their beautiful city? And if so, why? It’s a good thing the questions aren’t answered, he thought. If there were no more riddles on Venus, I don’t know what I’d do with my life.

  “The core here is supposed to be considerably smaller and less dense than Earth’s, isn’t it?” he went on. His curiosity was actually no more than mild, but he wanted to make conversation while they waited for the spacecraft.

  The young Chinese had arrived on the same ship which had taken Hawthorne home to furlough. Now they would be together for a long time, and it was well to show quick friendliness. He seemed a likeable little fellow anyhow.

  “True,” nodded Cheng-tung. “Though ‘supposed’ is the wrong word. The general assertion was proven quite satisfactorily quite some time ago. Since then Dr. Dykstra has been studying the details.”

  “I seem to have read somewhere that Venus ought by rights not to have a core at all,” said Hawthorne. “Not enough mass to make enough pressure, or something of the sort. The planet ought to have a continuous rocky character right to the center, like Mars.”

  “Your memory is not quite correct,” said Cheng-tung. His sarcasm was gentle and inoffensive. “But then, the situation is a trifle complex. You see, if you use quantum laws to calculate the curve of pressure at a planet’s center, versus the planet’s mass, you do not get a simple figure.

  “Up to about eight-tenths of an Earth-mass it rises smoothly, but there is a change at what is called the Y-point. The curve doubles back, as if mass were decreasing with added pressure, and only after it has thus jogged back a certain amount—equivalent to about two percent of Earth’s mass—does the curve resume a steady rise.”

  “What happens at this Y-point?” asked Hawthorne rather absently.

  “The force becomes great enough to start collapsing the central matter. First crystals, which had already assumed their densest possible form, break down completely. Then, as more mass is added to the plant, the atoms themselves collapse. Not their nuclei, of course. That requires mass on the order of a star’s.

  “But the electron shells are squeezed into the smallest possible compass. Only when this stage of quantum degeneracy has been reached—when the atoms will not yield any further, and there is a true core, with a specific gravity of better than ten—only thereafter will increased mass again mean a steady rise in internal pressure.”

  “Uh…yes. I do remember Wim speaking of it, quite some time ago. But he never did like to talk shop, either, except to fellow specialists. Otherwise he’d rather debate history. I take it, then, that Venus has a core which is not collapsed as much as it might be?”

  “Yes. At its present internal temperature, Venus is just past the Y-point. If more mass should somehow be added to this planet, its radius would actually decrease. This, not very incidentally, accounts rather well for the observed peculiarities. You can see how the accretion of material in the beginning, when the planets were formed, reached a point where Venus began to shrink—and then, as it happened, stopped, not going on to produce maximum core density and thereafter a steadily increasing size like Earth.

  “This means a smooth planet, with no upthrust masses to reach above the hydrosphere and form continents. With no exposed rocks, there was nothing to take nearly all the CO2 from the air. So life evolved for a different atmosphere. The relatively large mantle, as well as the low-density core, lead to a non-Terrestrial seismology, vulcanology, and mineralogy. The Venusian core is less conductive than Earth’s—conductivity tends to increase with degeneracy—so the currents circulating in it are much smaller. Hence, the weak planetary magnetism.”

  “Very interesting,” said Hawthorne. “But why the big secret? I mean, it’s a good job of work, but all you’ve shown is that Venusian atoms obey quantum laws. That’s hardly a surprise to spring on the universe.”

  Cheng-tung’s small body shivered a bare trifle. “It has been more difficult than one might suspect,” he said. “But yes, it is true. Our data now reveal unequivocally that Venus has just the type of core which it could have under present conditions.”

  Since Cheng-tung had during the night hours asked Hawthorne to correct any mistakes in his excellent English, the American said, “You mean the type of core it should have.”

  “I mean precisely what I said, and it is not a tautology.” The grin was dazzling. Cheng-tung, hugged himself and did a few dance steps. “But it is Dr. Dykstra’s brain child. Let him midwife it.” Abruptly he changed the conversation.

  Hawthorne felt puzzled, but dismissed the emotion. And presently McClellan’s ferry blazed out of the clouds and came to rest. It was a rather splendid sight, but Hawthorne found himself watching it with only half an eye. Mostly he was still down under the ocean, in the living temple of the Venusians.

  Several hours past nightfall, Hawthorne laid the sheaf of reports down on his desk. Chris Diehl and Mamoru Matsumoto had done a superb task. Even in this earliest pioneering stage, their concept of enzymatic symbiosis offered possibilities beyond imagination. Here there was work far a century of science to come. And out of that work would be gotten a deeper insight into living processes, including those of Earth, than men had yet hoped for.

  And who could tell practical benefits? The prospect was heartcatching. Hawthorne had already realized a little of what he himself could do, and yes, in a hazy fashion he could even begin to see, if not understand, how the Venusians had created that lovely thing beneath the water…But a person can only concentrate so long at a time. Hawthorne left his cubbyhole office and wandered down a passageway toward the wardroom.

  The station murmured around him. He saw a number of its fifty men at work. Some did their turn at routine chores, maintenance of apparatus, sorting and baling of trade goods, and the rest. Others puttered happily with test tubes, microscopes, spectroscopes, and less understandable equipment. Or they perched on lab benches, brewing coffee over a Bunsen burner while they argued, or sat feet on desk, pipe in mouth, hands behind head, and labored. Those who noticed Hawthorne hailed him as he passed. The station itself muttered familiarly, engines, ventilators, a faint quiver from the surrounding forever unrestful waters.

  It was good to be home again.

  Hawthorne went up a companionway, down another corridor, and into the wardroom. Jevons sat in a corner with his beloved Montaigne. McClellan and Cheng-tung were shooting dice. Otherwise the long room was deserted. Its transparent wall opened on seas which tonight were almost black, roiled and laced with gold luminosity.

  The sky seemed made from infinite layerings of blue and gray, a low haze diffusing the aurora, and a rain-storm was approaching from the west with its blackness and lightning. The only sign of life was a forty-foot sea snake, quickly writhing from one horizon to another, its created jaws dripping phosphorescence.

  McClellan looked up. “Hi, Nat,” he said. “Want to sit in?”

  “Right after Earth leave?” said Hawthorne. “What would I use for money?” He went over to the samovar and tapped himself a cup.

  “Eighter from Decatur,” chanted Jimmy Cheng-tung.

  “Come on, boys, let’s see that good old Maxwell distribution.”

  Hawthorne sat down at the table. He was still wondering how to break his news about Oscar and the holy place. He should have reported it immediately to Jevons, but for hours after returning he had been dazed, and then the inadequacy of words had reared a barrier. He was too conditioned against showing emotion to want to speak about it at all.

  He had, though, prepared some logical conclusions. The Venusians were at least as intelligent as the builders of the Taj Mahal; they had finally decided the biped strangers were fit to be shown something and would presumably have a whole planet’s riches and mysteries to show on later occasions. Hawthorne scalded his tongue on red bitterness.

  “Cap,” he said.

  “Yes?” Jevons lowered his dog-eared volume, patient as always at the interruption.

  “Something happened today,” said Hawthorne.

  Jevons looked at him keenly. Cheng-tung finished a throw but did not move further, nor did McClellan. Outside there could be heard the heavy tread of waves and a rising wind.

  “Go ahead,” invited Jevons finally.

  “I was on the trading pier and while I was standing there—”

  Wim Dykstra entered. His shoes rang on the metal floor. Hawthorne’s voice stumbled into silence. The Dutchman dropped fifty clipped-together sheets of paper on the table. It seemed they should have clashed, like a sword thrown in challenge, but only the wind spoke.

  Dykstra’s eyes blazed. “I have it,” he said.

  “By God!” exploded Cheng-tung.

  “What on Earth?” said Jevons’ mild old voice.

  “You mean off Earth,” said McClellan. But tightness grew in him as he regarded Dykstra.

  The geophysicist looked at them all for several seconds.

  He laughed curtly. “I was trying to think of a suitable dramatic phrase,” he said. “None came to mind. So much for historic moments.”

  McClellan picked up the papers, shuddered, and dropped them again. “Look, math is okay, but let’s keep it within reason,” he said. “What do those squiggles mean?”

  Dykstra took out a cigarette and made a ceremony of lighting it. When smoke was in his lungs, he said shakily: “I have spent the past weeks working out the details of an old and little-known hypothesis, first made by Ramsey in nineteen fifty-one, and applying it to Venusian conditions. The data obtained here have just revealed themselves as final proof of my beliefs.”

  “There isn’t a man on this planet who doesn’t hope for a Nobel Prize,” said Jevons.

  His trick of soothing dryness didn’t work this time. Dykstra pointed the glowing cigarette like a weapon and answered: “I do not care about that. I am interested in the largest and most significant engineering project of history.”

  They waited. Hawthorne began for no good reason to feel cold.

  “The colonization of Venus,” said Dykstra.

  -6-

  Dykstra’s words fell into silence as if into a well. And then, like the splash, Shorty McClellan said, “Huh? Isn’t the Mindanao Deep closer to home?”

  But Hawthorne spilled hot tea over his own fingers.

  Dykstra began to pace, up and down, smoking in short nervous drags. His words rattled out: “The basic reason for the steady decay of Terrestrial civilization is what one may call crampedness. Every day we have more people and fewer resources. There are no longer any exotic foreigners to challenge and stimulate any frontier…no, we can only sit and brew an eventual, inevitable atomic civil war.

  “If we had some place to go, what a difference! Oh, one could not relieve much population pressure by emigration to another planet—though an increased demand for such transportation would surely lead to better, more economical spaceships. But the fact that men could go, somehow, perhaps to hardship but surely to freedom and opportunity, that fact would make a difference even to the stay-at-homes. At worst, if civilization on Earth must die, its best elements would be on Venus, carrying forward what was good, forgetting what was evil. A second chance for humankind—do you see?”

  “It’s a pleasant theory, at least,” said Jevons slowly, “but as for Venus. No, I don’t believe a permanent colony forced to live on elaborated rafts and to wear masks every minute outdoors could be successful.”

  “Of course not,” said Dykstra. “That is why I spoke of an engineering project. The transformation of Venus to another Earth.”

  “Now wait a minute!” cried Hawthorne, springing up. No one noticed him. For them, in that moment, only the dark man who spoke like a prophet had reality. Hawthorne clenched his fists together and sat down, muscle by muscle, forcing himself.

  Dykstra said through a veil of smoke: “Do you know the structure of this planet? Its mass puts it just beyond the Y-point—”

  Even then, McClellan had to say, “No, I don’t know. Tell me w’y point?”

  But that was automatic, and ignored. Dykstra was watching Jevons, who nodded.

  The geophysicist went on, rapidly, “Now in the region where the mass-pressure curve jogs back, it is not a single-valued function. A planet with the mass of Venus has three possible central pressures. There is the one it does actually have, corresponding to a small core of comparatively low density and a large rocky mantle. But there is also a higher-pressure situation, where the planet has a large degenerate core, hence a greater overall density and smaller radius. And, on the other side of the Y-point, there is the situation of lower central pressure. This means that the planet has no true core but, like Mars, is merely built in layers of rock and magma.

  “Now such an ambiguous condition is unstable. It is possible for the small core which exists to change phase. This would not be true on Earth, which has too much mass, or on Mars, which does not have enough. But Venus is very near the critical point. If the lower mantle collapsed, to make a larger core and smaller total radius, the released energy would appear as vibrations and ultimately as heat.”

  He paused an instant, as if to give weight to his words.

  “If, on the other hand, the at-present collapsed atoms of the small core were to revert to a higher energy level, there would be blast waves traveling to the surface, disruption on a truly astronomical scale—and, when things had quieted down, Venus would be larger and less dense than at present, without any core at all.”

  McClellan said, “Wait a bit, pal! Do you mean this damn golf ball is liable to explode under us at any minute?”

  “Oh, no,” said Dykstra more calmly. “Venus does have a mass somewhat above the critical for existing temperatures. Its core is in a metastable rather than unstable condition, and there would be no reason to worry for billions of years. Also, if temperature did increase enough to cause an expansion, it would not be quite as violent as Ramsey believed, because the Venusian mass is greater than his Y-point value. The explosion would not actually throw much material into space. But it would, of course, raise continents.”

  “Hey!” That was from Jevons. He jumped up. (Hawthorne sat slumped into nightmare. Outside the wind lifted, and the storm moved closer across the sea.) “You mean…increased planetary radius, magnifying surface irregularities—”

  “And the upthrust of lighter rocks,” added Dykstra, nodding. “It is all here in my calculations. I can even predict the approximate area of dry land resulting—about equal to that on Earth. The newly exposed rocks will consume carbon dioxide in huge amounts, to form carbonates. At the same time, specially developed strains of Terrestrial photosynthetic life—very like those now used to maintain the air on spaceship—can be sown.

  “They will thrive, liberating oxygen in quantity, until a balance is struck. I can show that this balance can be made identical with the balance which now exists in Earth’s atmosphere. The oxygen will form an ozone layer, thus blocking the now dangerous level of ultraviolet radiation. Eventually, another Earth. Warmer, of course—a milder climate, nowhere too hot for man—cloudy still, because of the closer sun—but nevertheless, New Earth!”

  Hawthorne shook himself, trying to find a strength which seemed drained from him. He thought dully that one good practical objection would end it all, and then he could wake up.

  “Hold on, there,” he said in a stranger’s voice. “It’s a clever idea, but these processes you speak of—I mean, all right, perhaps continents could be raised in hours or days, but changing the atmosphere, that would take millions of years. Too long to do humans any good.”

  “Ah, no,” said Dykstra. “This also I have investigated. There are such things as catalysts. Also, the growth of micro-organisms under favorable conditions, without any natural enemies, presents no difficulties. Using only known techniques, I calculate that Venus could be made so a man can safely walk naked on its surface in fifty years.

  “In fact, if we wanted to invest more effort, money, and research, it could be done faster. To be sure, then must come the grinding of stone into soil, the fertilizing and planting, the slow painful establishment of an ecology. But that, again, needs only to be started. The first settlers on Venus could make oases for themselves, miles wide, and thereafter expand these at their leisure. By using specialized plants, agriculture can even be practiced in the original desert.

  “Oceanic life would expand much more rapidly, of course, without any human attentions. Hence the Venusians could soon carry on fishing and pelagiculture. I have good estimates to show that the development of the planet could even exceed the population growth. The firstcomers would have hope—their grandchildren will have wealth!”

  Hawthorne sat back. “There are already Venusians,” he mumbled.

  Nobody heard him. “Say,” objected McClellan, “how do you propose to blow up this balloon in the first place?”

  “Is it not obvious?” said Dykstra. “Increased core temperature can supply the energy to push a few tons of matter into a higher quantum state. This would lower the pressure enough to trigger the rest. A single large hydrogen bomb at the very center of the planet would do it. Since this is unfortunately not attainable, we must tap several thousand deep wells in the ocean floor, and touch off a major nuclear explosion in all simultaneously.

  “That would be no trick at all. Very little fallout would result, and what did get into the atmosphere would be gone again in a few years. The bombs are available. In fact, they exist already in far larger amounts than would be needed for this project. Would this not be a better use for them than using them as a stockpile to destroy human life?”

  “Who would pay the bill?” asked Cheng-tung unexpectedly.